An agricultural row crop planter is a machine built for distributing seed into the ground. The row crop planter generally includes a horizontal toolbar fixed to a hitch assembly for towing behind a tractor. Row units are mounted to the toolbar. In different configurations, seed may be stored at individual hoppers on each row unit, or it may be maintained in a central hopper and delivered to the row units on an as needed basis. The row units include ground-working tools for opening and closing a seed furrow, and a seed metering system for distributing seed to the seed furrow.
In its most basic form, the seed meter includes a housing and a seed disc. The housing is constructed such that it creates a reservoir to hold a seed pool. The seed disc resides within the housing and rotates about a generally horizontal central axis. As the seed disc rotates, it passes through the seed pool where it picks up individual seeds. The seeds are subsequently dispensed into a seed chute where they drop into the seed furrow.
Seed spacing in the seed furrow is controlled by varying the rotational speed of the seed disc. Most commonly, seed disc rotation is driven by connection to a common driveshaft. The driveshaft runs horizontally along the length of the toolbar to connect to each row unit, and is driven by a single motor or a ground contact wheel. In this configuration, the planting rate can be adjusted for all row units uniformly by adjusting the rotational speed of the common drive shaft. This can be a tedious task, and an operator is unlikely to adjust the gear ratio as often as necessary to maximize yields. Generally, an optimal overall rate for a given acreage will be selected prior to planting and will be maintained at that rate regardless of soil conditions. Whether using a mechanical, air, or vacuum style seed disc, the seed disc is installed inside of the seed meter using independent fasteners and requires the use of tools to facilitate changing the disc. For example, if a farmer uses the same planter to plant corn and soybeans, he would use a different disc for the respective seed types. With planters continuing to grow in size, and more row units being added, the task of changing seed discs using independent fasteners and tools adds unnecessary burden to changing out seed discs.
More recently, planters have been designed to provide for independent driving of each of the seed discs in each seed meter. The meters include a motor, such as an electric motor, that is attached to the meter. The output shaft extends from the motor and into the meter such that a portion of the shaft is operatively connected to the seed disc. Therefore, the motor will operate to rotate the seed disc.
The most common seed delivery system for delivering seed from the seed disc to the furrow may be categorized as a gravity drop system. In the case of the gravity drop system, a seed tube has an inlet end, which is positioned below the seed metering system. The singulated seeds from the seed metering system drop into the seed tube and fall via gravitational force from a discharge end thereof into the seed trench. Monitoring systems are commonly used to monitor the operation of the planter. Such systems typically employ a seed sensor attached to each seed tube to detect the passage of seed therethrough.
However, such a gravity system can affect the seed spacing of the planter. For example, as the spacing of the speed is dependent on the rotational velocity of the seed disc and the gravitational constant, interruptions, forces, or other occurrences acting on the seed can greatly affect the spacing. For example, if the seed bumps against a wall of the seed tube on the way to the furrow; this can cause a delay or a non-vertical fall of the seed. If a preceding or following seed does not experience the same interruption, the seeds could be spaced too close or far from one another.
Furthermore, as the speed of planting increases, this causes additional problems. Drawing a planting implement through the field at faster speeds increases the speed of deposited seeds relative to the ground, causing seeds to roll and bounce upon landing in the trench or furrow and resulting in inconsistent plant spacing. The adverse agronomic effects of poor seed placement and inconsistent plant spacing are well known in the art.
Therefore, there is a need in the art for an agricultural planting implement that includes a seed delivery apparatus that aids in delivering seed from a singulating seed meter to a furrow or trench in the field, such that the spacing of adjacent seed is more consistent to increase the yield obtained of the end crop.